From clc-wiki

Contents 1 Description 1.1 Fmt 2 Return value 3 Prototype

Description

The printf() function writes data formated as specified in the string fmt, to the standard output stream.

Fmt

All characters in fmt are printed as is, except for formating directives starting with %. Each of these directives correspond to one argument in the variable argument list. In addition to the %, a directive contain optional flags and a conversion type.

These are the conversion types:

code	conversion	data type
d	signed decimal	int
i	signed decimal	int
u	unsigned decimal	int
o	octal	int
x	hexadecimal lower case	int
X	hexadecimal upper case	int
f	decimal notation	double
F	decimal notation	double
e	e notation	double
E	e notation	double
g	decimal or e notation	double
G	decimal or e notation	double
c	character	char
s	string	char *
P	address	void *

Usage example:

#include<stdio.h>

int main()
{
    int n=5;

    printf("n=%d\n", n);
    return 0;
}

Full program, strictly conforming; public domain; past reviewers: {{{past-reviewers--no-line-breaks}}}; current reviews: {{{later-reviews--"none"-or-empty}}}

Return value

If successful, the printf() function returns the number of written characters. To indicate an error, -1 is returned.

Prototype

Declared in stdio.h

The C89/C99 prototype is:

int printf(const char *fmt, ...);